Process for the manufacture of molded pieces from mortar or concrete



Nov. 16, 1937. E. FREYSSINET 2,099,265

PROCESS FOR THE MANUFACTURE OF MOLDED PIECES FROM MORTARS OR CONCRETE Filed Fb. 5, 1954 4 Shets-Shegt 1 wlkilwllw 4 Sheets-Shet' 2 E. FREYSSINET Filed Feb. 5, 1934 Nov. 16, 1937.

PROCESS' FOR THE MANUFACTURE OF MOLDED PIECES .FROM MoR ARs 0R CONCRETE I 'Nov. 16, 1937.. FREYSSIYNET 2,099,265

PROCESS FOR THE MANUFACTURE OF MOLDED PIECES FROM MORTARS OR CONCRETE Filed Feb. 5, 1954' 4 Sheet'S-ShGGQ 3 Nov. 16, 1937. E. FREYSSINET 2,099,265 PROCESS FOR THE MANUFACTURE-OF MOLDED PIECES FROM MORTARS 0R CONCRETE Filed Feb. 5, 1934 4 Sheets-Sheet 4 I Isa 13 9 ""158 is: J

. 3e r31 $55 134 A a a:

" I II .1!!! II I I 1/! 1 I 1 I I l 4 v 1 r u 1 I I I Patented Nov. 16, 1937 J 2,099,265

PROCESS FOR THE MANUFACTURE OF PIECES FROM MORTAR OB CON- Eugene Freyssinet, Neuilly-sur-Seinc, France Application February 5, 1934, Serial No. 709,87!

. In France February 9, 1933 4 Claims. (01. 25-155) The present invention relates to methods and organs acting as knives or plugs making it posapparatus for the manufacture of molded pieces sible to obtain, after removal of these comple-. or bodies from mortars. or concretes that are moistmentary chambers, very clean and regular limitand even contain an excess of water, in which ing surfaces for the concrete, without any risk of 5 methods these concretes or mortars are subjected concrete dropping from the complementary 5 to the action of a vibration and a compression, in chambers when they are removed.

order to drive out the excess of water and to The combination of these two features makes it rapidly produce an' article having the maximum possible to obtain a perfect result from the point hardness that is possible. of view of both the compactness and the homo- Ihave found out that vibration causes a settling geneity of the concrete that is obtained. These 10 of the concrete at the lower part of the mold while two features are closely interrelated because the the excess of water accumulates in the upper part compression of the concrete in the mold, during which thus becomes filled with soft concrete. the vibrating treatment, can be advantageously Under these conditions, compression produces deobtained under the effect of the pressure resulting formations of the concrete that'vary according-to from the height ofconcrete filling the comple- 15 the level in the mold and the articles thus obmentary chambers, provided that these chambers tained may be utterly spoiled. are suitably disposed above the mold.

On the other hand it is important, in order to Other means for creating the desired pressure keep the deformable or expansible organs serving in the mass of concrete in the mold may consist 0 to compress the concrete in good working order, of one or several pistons adapted to compress the and also in order to obtain regularly and accuconcrete in the molds, these pistons being either rately shaped articles, that the deformations of partly immersed directly in the concrete or disthese organs should be small, corresponding for posed inside a corresponding cylinder. They may instance to a small reduction of thickness of the be made in any suitable manner, consisting for as concrete in the mold. I instance of rods or bundles of rods, made of steel,

A first feature of the method according to the wood or any other material, bearing on the conpresent invention consists in performing the crete, slight spaces being reserved between them treatment in two steps, one that consists in'simuland the cylinder for the escape of the excess of taneously vibrating and compressing the concrete, water, air, etc. These pistons may act either by the compression being relatively weak, in order their own weight 0r*be subjected toother loads. 30 that it may not prevent the relative displacement I may also place at a suitable point, for instance of the concrete particles under the effect of the in a complementary chamber, an expansible elevibration, and the second step consisting in ment, such as a rubber bag which will be inflated strongly compressing the concrete which has been by means of water or air. Finally, I may also rendered firm and compact by the first step of the make use of a concrete pump for filling the mold 35 treatment. and subject the concrete therein to the desired Another feature of my invention consists in pressure. connecting .with the portions of the mold in I must further provide in the mold apertures which the concrete has a tendency to become too adapted to prevent the concrete, including the fluid complementary chambers which are filled fine particles thereof, from escaping from the 40 with concrete at the same time as the mold. mold, while allowing Water and air to be driven These chambers are so arranged that the portions out therefrom, these apertures being locatedsufli of the mold that have a tendency to become exagciently below the free surface of the concrete for geratedly fluid in the course of the vibrating treatcausing the concrete in the vicinity of Saidaperment are transferred into said chambers so that tures to undergo a sufiicient pressure for compact- 45 the mold finally contains only concrete having a ing the solid elements thereof while facilitating homogeneous structure. the escape of air and water in excess.

I thus obtain that the mold is exactly filled with Inorder to carry out the method above exconcrete. The complementary chambers can be plained it is particularly advantageous to make separated without difficulty by producing a relause, for constituting the complementary cham- 50 tive sliding displacement of the complementary her that serves both to subject the concrete in g chambers and of the mold along their joining surthe mold to the required pressure during the vi-' face, which must be eithera plane surface of a brating treatment and to receive" the portions :of surface of revolution. The complementary chamthe concretethat'are too fluid, of a hopper'of bers may be provided along these surfaces with suflicient height, located above the mo1d,'with 55 another.

which it communicates. This hopper will further serve to the filling of the mold and to vibrate the concrete in the mold due to the vibrations of its walls and of the walls of the mold which are temporarily rigidly connected with said hopper.

. My invention further includes a particular application of the method above set forth to the manufacture of articles of any shape and size by successive elements perfectly connected to one For this purpose, I provide, on the one hand, temporary connecting organs between each finished element and the mold that is to serve to the manufacture of the next element, these organs being capable of withstanding the stresses which, due to the vibrating and compressing treatments, will tend to separate the concrete 1 already hardened from. the next element to be fixed thereto; and on the other hand, permanent connecting organs between the successive elements. The temporary connecting organs between the concrete and the mold can be obtained by providing in the outer portions of the mold an end element the walls of which are in contact with the concrete are corrugated or rough, so as to adhere strongly thereto, this element being left in position until the concrete is hardened and is sufficiently strong for resisting the eiforts to which it will be subjected in the course of the following operations. The connection between the concrete and the mold may also result from holes provided in the concrete and adapted to cooperate with bolts or other, known connecting means. The connection may also be insured by means of organs sealed in the concrete, such as inwardly threaded rods, bolts or fastening rings. The permanent connecting organs may consist of reinforcements projecting from the concrete or of recesses provided in the latter and intended to be molded with the following element. For instance the inner expansible elements are providedwith one or several projections at their end located on the side where the next element is to be added, said projections being of suitable shape for providing in the molded concrete a recess of corresponding shape in which will be inserted the reinforcements and the concrete through which an element is rigidly connected with the next element. Special expansible elements can be substituted for one or several of these projections.

Other features of my invention will result from the following detailed description thereof.

Preferred embodiments of the present invention will be hereinafter described with reference to the accompanying drawings, given merely by way of example, and in which:

Figs. 1 and 2 are diagrammatical views illustrating means for obtaining a moderate compression of the concrete during the vibrating treatment;

Fig. 3 shows, partly in'sectional view and partly in diagrammatic perspective view, a device for carrying out the process according to my invention which includes a hopper for filling the mold, which also acts as means for compressing the concrete in the mold, complementary chamber, and. vibrating means;

Fig. 4 shows how the mold can be closed after being filled with concrete;

Figs. 4a and 4b a cross section on the line la-4a of Fig. 4b and a side view respectively of another device for closing the mold;

Fig. 5 shows a vibrating device disposed on the inside of the core;

Fig. 6 is a cross section of an expansible organ consisting of a plurality of staves subjected to the Y action of an elastic mandrel Figs. 7, 8 and 9 show details of this expansible organ;

Fig. 10 is a sectional view of a mold provided with an expansible organ of this kind;

Figs. 10a. and 1012 are a crosssection and a longitudinal section respectively of a device for closing the ends of the elastic mandrel;

Fig. 11 is a diagrammatical view of another :embodiment of the device for closing the end of the mandrel;

Fig. 11c shows a device for operating the cores;

Figs. 12 to 15 are diagramm'atical views illustrating other embodiments of the invention;

Fig. 16 is a vertical sectional view illustrating the manufacture of concrete piles or stakes by successive elements;

Fig. 17 is a diagrammatical view illustrating the manufacture of a large size building element, for instance a bridge arch.

Figs. 1 and 2 show a mold wall I having a series of points a, b, c, d,--h located at a higher level where there have been provided different devices for obtaining a moderate compression of the concrete I in the mold and for simultaneously allowing water and air to escape; 2 is a plug consisting of a plurality of wooden plates which do not fit exactly with each other, said plug being maintained by a plate 3 and a screw 4; 5 is another plug made of a filtrating material, suchas felt, horse-hair, etc., maintained in position by a removable plate 6, fixed by means of screws and nuts I; 8 is an autoclave joint which is not watertight, which is kept in position during the filling of the mold by an elastic organ 9; H1 is an external closure plate maintained by a screw II; I2 is a plunger piston acting in a cylinder l3 which may be used as a filling hopper and as a complementary chamber, this piston being actuated by a hydraulic jack l4 so as to compress the concrete in the mold; I5 is a floater reducing to a minimum the volume of concrete contained in a complementary chamber I6; I! is a piston consisting of a plurality of rods or blades resting on the surface of the concrete and allowing water to leak out through the interstices between them; I8 is a rubber bag inflated through a pipe l9 and'acting in a chamber 211 closed by joints 2|, 22 that are not watertight.

In Fig. 3, the mold consists of two mold elements 23, 24 assembled along their lower edge througha longitudinal autoclave joint 25 forming a double joint for the escape of water and also through jaws 26 coacting with a yielding organ 21, for instance made of wood and provided with holes, so as to form a flexible joint allowing water, and even concrete, to leak out.

Between the upper edges 28, which are thick, rigid and horizontally disposed, of this mold, I provide two steel lips 29 having a rubber coating which projects inwardly at 30. These lips prolong the walls 3| of a sheet iron hopper supported by members 32 resting on rubber parts 33. This hopper is closed, at its front and rear ends, by metal plates 34 connected together by a rubber membrane 35, or any other organ permitting a displacement of walls 3| with respect to each other. These walls 3| can be pushed toward each other, so as to close the passage between projections 30, by operating hydraulic jacks 36 acting through suitable levers on rubber-pads 31 carried by the walls of the hopper. On the contrary these walls 3| can be moved away from each other so as to open this passage between projections 30 (when the mold is being filled) by discharging the working water from these jacks.

Other hydraulic jacks 38, distributed along the hopper and bearing against the edges 28 of the mold, can strongly apply these edges against the lips 29 of the hopper.

Each element of thehopperis connected with bearings 39 distributed over its length and in which are joumalled shafts 40a, 40b carrying,

close to said bearings, eccentric masses 4m, 4ib disposed in the same plane for each of said shafts. Bearings 39, shafts 40a and 40b, and also masses 4 la, 4 lb are symmetrically disposed to the vertical median plane of the hopper. Shafts 40a,

ficiently rigid for maintaining'a sufficient syn-- chronism of the movements of the shafts. In the embodiment of Fig. 3, these coupling organs include a fork-shaped piece 43 the ends of which are surrounded by rubber cylinders 44 engaging in corresponding recesses 45 rigidly connected to the portion of the shaft driven by the bevel gear wheels.

In the case of hoppers and of molds of great length, similar organs can be interposed between several portions of shafts 40a and dill), in order to facilitate the taking to pieces.

When the gear wheels are actuated by a motor 46, the bearings 39, the walls 3i of the hopper, and also'the lips 29 at the lower part thereof are given symmetrical vibratory -movements, the amplitude of which depends on the ratio of the masses depending on the hopper and the product of the eccentric masses and of their eccentricity.

on the other hand, the intensity of the vibratory accelerations increases proportionally with the square of the speed of revolution.

It is therefore to vary at will the amplitude of the movements of the mold and the energy of the vibratory movement independently of each other, by varying the eccentric masses and'the speed of revolution of the shafts that, carry said'masses,

This vibration is transmitted to the mold through lips 29 when pressure is applied thereto through jacks 38. 'I h'e passage between said lips is opened and closed several thousands of times per minute (the width of this passage being for instance of about 1 millimeter, although it can be considerably greater orsmaller) and the walls of the mold and the system consisting of wood piece 21 and jaws 26 are'elastically deformed.

The value of the alternating accelerations is about ten times the acceleration of gravity; but this is merely an indication and these alternating accelerations-might be considerably greater or smaller. I Y

Concrete'in the plastic state and even in a relatively firm state, when poured into the hopper at any point thereof during the vibratory treatment, assumes the appearance of a liquid, having a horizontal level surface, so that the mold is perfectly filled, even in its smallest interstices, and moreparticularly in the vicinity of reinforcements such as I I3, which have been disposed in advance in the mold. l

Furthermore, if the amount of concrete'lntroduced into the hopper is greater than that necessexy forfllling the mold, so that, once said mold is full, as certain amount of concrete remains in the hoppers, up to a height h the concrete in the mold is compressed, during the whole vibrating treatment, with a pressure the value of which depends on n. 7

Finally, the hopper plays, during this vibratory treatment,- the. part of a complementary chamber as above explained. the excess of water in the concrete of the mold accumulating in the upper part of the concrete in the hopper, while the vibratory treatment causes the solid particles of said concrete in thehopper to pass into the mold which is thus filled with homogeneous concrete at the end of the vibrating treatment. This treatment lasts for some minutes, after which motor 46 is stopped and water is discharged from the hy-.

draulio jacks 38, jacks 36 being kept under pressure. The mold, now exactly full with compact concrete can then be separated from the hopper by moving in a downwarddirection'support 41,

.for instance by means of jacks 48. The orifice between the upper edges 28 of the mold is then stopped by meansof a plate of wood, metal or both of these materials, 48, which can be maintained in position through any suitable known means, for instance by means of jaws 28" '(Fig. 4) orby straps H0 (Figs. 4a and 4b) applied by means of tightening elements the tension of which can be adjusted by means of a screw engaging in element H2.

When the mold is thus closed the concrete therein can be subjected to the second part of the process according to the present invention which consists in strongly compressing it by means of an expansible mandrel disposed inside the mold and made, for instance, as it will be hereinafter described Vibration can be produced through many other means. In some cases, it will be advisable to produce it by the rotationof eccentric masses such as 50 (Fig. disposed on the inside of the mold'itself, for instance in the expansible central core 54 said masses being carried by shaft 52 the bearings of which are rigidly supported by said core. Instead of being transmitted to the mold through the hopper, as in the embodiment of Fig. 3, the vibrations can also be'directly transmitted to the walls of the mold, by connecting said walls with the bearings of the shaft carrying the eccentric revolving masses.

The 'expansible organs serving to carry out th second part of the process according to the present invention and on which the concrete is molded during the first part of the process must have a rigid and definite shape so as to permit of obtaining correct molded articles of uniform thickness, even during this first step of the process.

These expansible organs are of two kinds.

, In the first kind, an example of which is shown .in Figs. 3 to 5 inclusive, and more specifically in Fig. 4a, there is provided a rigid core SI of wood or metal of the desired shape covered by an elastic bag 53, for instance ofindia-rubber,

which will be generally strengthened by fabrics or cables such as 53 in at least one direction, owing to the small deformation to which these organs are subjected. A fluid is introduced at the desired time between the core and the bag an india-rubber expansible envelope 53, either could also be dispensed with by giving a suitable free or mounted on a rigid mandrel 5|, as in the shape to the end of the elastic envelope, which preceding case. These staves are suitably shaped is supposed to be reinforced in the longitudinal so as to constitute, when they are assembled todirection by means of inextensible wires, of fibre, gether, a well determined structure, against textile material or metal.

which concrete can be molded in an accurate The deformation of the concrete that results manner. If the elastic envelope 53 is inflated by from its being compressed increases the inner means of a fluid under pressure, the staves are volume, thus creating a play which will permit, pushed apart, thus compressing the concrete and as a rule, to remove the expansible organ. If opening between them very fine interstices for the the core is of elongated shape and horizontally outflow of water, the width of these interstices indisposed, its removal by causing it to slide out creasing as the concrete is being more compressed, from the fresh concrete article may be somewhat so that the outflow of water from the concrete diflicult. This difliculty can be obviated by suptakes place under the best conditions, this outporting it at a single point of its larger end by flow being eventually facilitated by providing means of a carriage such as that shown in Fig.

grooves in the sides of the staves. In order to 11; This carriage I can be engaged under the avoid that the elastic envelope may engage into mold so that the center of gravity I3I of the the interstices between the staves, the latter will core may be located between the ends I32, I33 be provided with pieces such as 58 (Figs. 7 and 8) of the carriage. The latter comprises longitudimade of metal, wood, stronger india-rubber, or a nal wheels I34 and transversal wheels I35, which fabric of suitable shape, normally folded for incan be brought into inoperative positions by any stance so as to permit the expansion of india- 7 known device such as that including articulations rubber while preventing it from penetrating into I36 and levers I3'I. Wheels I34 can be adjusted the interstices between the staves. The same reat any desired height by means of springs I38 suit can be obtained by means of wires 51 disposed balancing the weight of the system. The core very obliquely with respect to the generatrices of is provided with a part I39 pivoted about an axis the cylinder (Fig.9). I40 to the frame of the carriage. A lever I In both of the embodiments just above dehaving an arcuate portion I42 acting as a pulley scribed, the elastic bag or envelope may consist having its center on axis I40 is also pivoted to of various materials of elastic structure arranged the frame about said axis or one located very in various manners. It may for instance consist close to it. This lever I4I can be actuated of a double rubber wall forming a closed flat bag through a mechanism I43 including for instance which may be inflated through an aperture such a screw. as the valve of the inner tube of a pneumatic Cables I44 adapted to slide in tubes I45 are tire. It may also consist of a fiuidtight internal secured to points I46 of the core. These cables mandrel with an external rubber envelope joined pass over portion I42 and are fixed to lever I to said mandrel through any suitable means such at I". r as: an autoclave joint analogous to a cup-leather An action on these cables produces reactions packer, or an elastic envelope inserted between converging at I40, the vertical components of the core and an external envelope and inflated which.at points I46 balance the weight of the at a pressure higher than that existing between core. Points I46 may be so determined that the the pe and the mandrel. elastic deformation of the core when it is lifted This la r n ment w ll be m p ifi lly by acting thereon through I43, produces no other described with reference to Figs. 10a and 10b, deformation than a longitudinal compression.-

which correspond to the type of mold and -of The core is thus supported under conditions such elastic mandrel shown in detail in Figs. 4a and that its handling becomes very easy. 4b. A plate III, made of such a size that it may I may also facilitate the removal of the core cover the extreme edges of the mold portions by making it of several parts one of which, 23 and 24, is provided in its middle part with a in the shape'of a wedge, will permit the removal hole accommodating core 5I and elastic envelope of the others. In the case of mandrels consist- 53- Around s hole there s fixed a utter ing} of an assembly of staves, it will be advanshaped hollow part H8 in which is mounted an tageous to insert between two'staves, a steel blade elastic tube II9 of the kind of the inner tube such as 53, having parallel or slightly divergent of a pneumatic tire, and adjusting elements such faces (diverging toward the inside of the mold), as I20 and I2I, which may be made of rubber, which will be easily driven in toward the center, strengthened in a direction parallel to the axis once the pressure exerted through the elastic of the mold. If a fluid under a suitable pressure envelope is removed. is introduced into this tube H3, it strongly ap- By means of one or the other of the ex- DlieS s c envelope 53 against co e 5 The pansible organs above described, or by their comelements I20 and I2I make it possible to varfl/fleination, it will be possible to obtain recesses of to a substantial degree the size of the cores that (any desired shape, either simple or multiple, can be utilized with the device. The whole must either cylindrical or of. complex shape, provided be maintained against the end of the mold in with grooves'if the expansible organs are located any suitable manner for resisting the pressures. at the periphery of the mold, etc. It will be also I .have shown in Fig. 11 a second examplein possible to make use of ver'y flat expansible ele- Which an e astic e pe 53 is disposed a d ments disposed between the wall of the mold and a rigid core 5|, staves 55 being arranged around the concrete, such as shown at 61 in Fig. 15. In said envelope. The elastic envelope 53 is main- Fig. 10, an auxiliary expansible organ I2 distained at the ends of the core by an end plate posed in the annular mass of concrete permits 58 which bears against shoulders provided in of obtaining a conduit therethrough and a secstaves 55. This end plate 58 and the plate located 0nd expansible organ 13, provided at the periphat the other end of the mold could' also be ery of the concrete permits of obtaining a groove. maintained by metal rods, wires, or cables pass- The reduction of the volume of the mold can ing through holes or grooves provided in the also be obtained in other manners without destaves (wires 10, Fig. 16, holes 'II, Fig. 6). They parting from the'principle of the present invention. For instance. as shown in Fig. 12, the mold can be made of two portions 80, 6|, part 60 being stationary and part ll being movable by means press the concrete between these molds by means of plates 65 between which are mounted jacks 6', rubber bags, or equivalent means. In Figs. 14 and 15, the mold is divided into several portions by several expansible organs 61.

The pressure applied during the second part of the process may vary between some hundreds of grammes per square centimeter and some hundreds of kilogrammes per square centimeter. The only limits that exist are imposed by the necessity of making sufllciently strong molds.

' The results that are obtained are so much the better as the pressure is higher. This is why it is important to make molds as strong as possible,

by providing them with reinforcing members as in the embodiment shown in Figs. 4a and 41), or by giving their section a suitable shape, for instance a circular shape, the parts being assembled by means of screw jaws 26 acting tangentially to the curve of tensions in the metal of the mold (Fig, 10). However, it is possible to produce with these "molds articles of ,any desired section by distributing at the proper places cores of suitable shape. It is also possible to utilize molds formed by walls of any shape whatever, adapted to the special use that is considered, said walls being. connected together, and particularly through the -concrete, by bolts' extending through tubes of concrete prepared in advance and which are left in the mass or surrounded by tubes of rubber or any other plastic material permitting their removal and an example'of which will be described with reference to Fig. 17.

As a rule, no vibration will be effected during the final compression because vibration may, in this case, produce a settling of the concrete around the lower portions of the core, so that the increase of volume resultingfrom the compresi5 sion 'willtake place only at the upper part of the latter," this involving an irregular form of the finished article, difliculties in the removal from themold, and frequently the injuring oi the expansible organs.

In special cases in which such drawbacks are not to be feared, it is however possible to main-v tain thev vibratory treatment during the second part of "he process,-because it will facilitate the 'outiiow f the excess of water, which, due to the stop ing of the vibratory treatment, becomes more difilcult. In such cases, the second-step of the process is a mere continuation of the first one,.characterized by the use of a higher pressure.

stronger than-concrete articles molded in the dry. stateand compressed in a press. Furthermore, xtheconcreteyis very-:adhesive to its reinforce mer ts, ,fl'hislconsistency permits in any case immediately toremove the concrete piece from either the innerJ'or the outer mold and veryotten irom both at the sametime, even when the i'pi eees are of complicated shape, or very thin, or

oi very large size.

The hardening of concrete treated by the process above described is extraordinarily rapid. In the case of pressures averaging 20 kilogrammes per square centimeter applied to concretes sufflciently rich in very fine elements, I obtain, with good aluminous cements, -at an average temperatureof 15 0.:

3 hours after the tempering a resistance of from 150 to 300 8 hours after the tempering a resistance of from 400 to 800 18 hours after the tempering a resistance of from 500 to 1000 With Portland cements equivalent resistances are obtained after periods of times above four or five times longer, at the same average temperature of 15 C.

By heating progressively from 15 to'80" C. or 90 C. in a saturated atmosphere and under conditions capable of avoiding dehydrating of the concrete, it is possible to shorten the times of hardening for Portland cements down to the values above indicated for aluminous cements. In this case, there is a difiiculty that results from the heat of setting of the cements which tends, by raising their temperature above that of the heating medium, to dehydrate them the more rapidly as they contain but just the amount of water that is necessaryfor their setting, which prevents their hardening. A concrete at a temperature of 85 becomes quickly dehydrated in air at a temperature of 80, even saturated with water vapor. This drawback can be obviated by progressively increasing the temperature of the vapor around and into the concrete article to be heated, placedin a heat insulated envelope, consisting eventually of the mold itself, with an, adjustable rate of flow so as to obtain the desired law of variation.

I have found that, in order to further increase the-"rapidity of hardening, it suflices to let a certain time elapse between the end of the first step of the process and the beginning of the second, this time being suflicient for causing the setting to have started when the high pressures applied during the second step of the process are brought into play. I may also, for the same purpose, prolong the first step of the process until the setting of the concrete has'started.

I may further indicate, as one of the results of the quick hardening of the-concrete and of the regularity ofmolding which result from the process according to the present invention, the I possibility of manufacturing objects of unlimited length and width,- and of any desired shape, by making it in successive portions perfectly well connected and secured to one another.

I will describe two examples of such a manufacture. The first example will be explained with reference to Fig. 16 of the accompanying drawings which illustrates a. method of manufacturing piles the successive portions of which are molded vertically after sinking of the preceding portions.

The outer portions of the mold are provided with an end element 8| whose wall in contact with the concrete is corrugated or rough so as to adhere strongly thereto. In Fig. l6- the end element 8| is in position at the upper part of a pile portion Apreviously manufactured and sunk.

Kg/cm Y I The question is now to make the following portion B. I place over end element 8| a cylinnuts in lugs 83 provided on the end elements.

' rods 88 fixed in the lower lugs 83.

In the mold thus formed I place an expansible cylindrical organ consisting of a rigid core 5|, a rubber envelope 53 and staves ii, the core and the staves being maintained in position by means of wires or rods 18 extending through grooves provided in the staves and connecting the end plates 58 together. This core further comprises at its upper end an annular-projection 84 reducing at this place the interval between the core and'the mold. In the manufacture of portion A-of the pile, this projection 84 has produced-an annular recess which is visible at 84 and which will serve to connect portions A and B together. The connecting reinforcements 85, distributed in the concrete of portion A project into this recess.

I may also provide other cores such as those shown in Fig. 10 at 12 and 13, the last mentioned cores being or not provided with projections.

These projections of the expansible organs can be replaced by special expansible cores of suitable length adapted to reserve sufllcient recesses for a good sealing of the connecting reinforcements.

I dispose, above the interval between the core and the mold, an annular hopper 85 and I pour thereinto an amount of concrete sufficient for filling the mold and the hopper up to a height h. The concrete is vibrated in the course of this filling, for instance by rotating, in bearings rigidly connected with the mold, shafts carrying eccentric masses, or in any'other way. This vibratory treatment is prolonged for a sufficiently long time, once the mold is full, for driving out the excess of water. The hopper then plays the part of a complementary chamber and of an organ for moderately compressing the concrete in the mold, owing to the amount of concrete that it contains. After eliminating the air and the water in excess in the mold and obtaining therein a compact and homogeneous concrete, the hopper is removed and it is replaced by a closure plate 81 (shown in dotted lines in the drawings) connected to the end element 8| by Fluid under pressure is then introduced into the elastic envelope through pipe 88 so that the excess of water of the concrete fiows out through the staves. This compression, which pushes the concrete toward the outside, has for its effect to weld the lower part'of portion B with the upper part of portion A previously manufactured in the annular recess '84 provided at the upper part of the last mentioned portion of the article 7 to be obtained- The pressure is removed, the

elastic mandrel, the staves, then the portions of the mold and finally. end element 8| are removed. I leave in position the end element 8| which reinforces the end of portion B against the stresses that it may have to withstand in the course of the following operations, for instance for sinking it. The following portion of the pile is then added in the same manner to portion B and so on. The end elements and the shells of the mold are made of two parts assembled together by means of screw jaws as shown in Fig. 10, so as to permit of readily placing and removing them.

This method of manufacture is applicable in particular to screwed piles. It is also possible to build a pile that is sunk in the ground and then prolonged upwardly, with or without a change of section, owing to the use of suitable molds, so as to obtain a pillar made of a single piece.

The second example relates to the production of large monolithic buildings of reinforced concrete, beams or arches for bridges, to which the process according to my invention gives the ad-. vantage of an immediate striking of the center, even for considerable spans and extraordinarily high resistance to load. I may for instance build an arch made of elements of any section whatever, for instance of rectangular section. The mold shown in Fig. 17 consists of walls 88 and 8|, assembled together and braced by means of bolts 82 passing through concrete tubes 83. It is caused to vibrate by the rotation of eccentric masses, not shown in the drawings carried by shafts turning in bearings fixed to the wall 88 ,or to a filling hopper placed at a higher. level, or

through any' other means. This mold consists of wall elements 88, 88 which will adhere to the concrete and are intended to remain fixed thereto; it further comprises cores 84 for the housing ofconnecting reinforcements, and other elastic cores 85 for the compression of the concrete, which maybe fiat as shown at 85". The concrete piece that is shown in the drawings can be developed by connecting it with contiguous elements added subsequently, in directions indicated by arrows F F and F by making use of mold walls. such as |8|, |8|'*, I82, I82, I88, I83 shown in dotted lines, prolonging the mold 88, 8| and fixed either to the connecting elements 88'; 8|, or to the walls 88, 8|, through any suitable means, eventually by means of a portion of the bolts 82 already utilized, after removal of theportions of the molds such as 88, 8|'. The permanent connection between the successive concrete elements will be insured by holes provided in cores 84 and/or projecting reinforcements 86. The last mentioned reinforcements may be very short andbe prolonged by autogeneous welding, especially by utilizing the processes described in my French Patent No. 708,726, filed April 8, 1838. The concrete piece may also be prolonged in a direction at right angles to the plane of the drawings, the connecting holes being then provided in cores disposed as at 85.

The last example shows that the advantages of my invention can be applied to constructions of any shape and size for which a high resistance of the concrete and a quick hardening are desirable.

While I have described what I deem to be practical and efhcient embodiments of my invention, it should be well understood that I do not wish to be limited thereto as there might be changes made in the arrangement, disposition and form of the parts without departing from the principle of my invention as comprehended within the scope of the appended claims.

What I claim is: Q

1. A process of manufacturing hollow concrete articles which comprises pouring wet concrete into a mold, fiuldifying said concrete in said mold by rapid vibration and simultaneously subjecting said liquid concrete to a pressure sufficiently low for permitting relative displacements of the particles of the concrete in the liquid mass, stopping the vibration when the concrete has become firm and finally subjecting said firm concrete in'the 7.

mold to a high pressure exerted from within the concrete mass. I

2. A process of manufacturing hollow concrete articles which comprises pouring wet concrete into a mold and into a chamber communicating with the upper part of said mold, fluiditying said concrete in said mold and in said chamber by rapid vibration exerted on saidmold and said chamber and simultaneously subjecting said liquid concrete to a pressure suiliciently low for permitting relative displacements of the particles of the concrete in the liquid mass, stoppingthe vibration when the concrete has become firm in the mold and finally subjecting said firm concrete in the mold to a high pressure exerted from within the concrete mass. 3. A process of manufacturing hollow concrete articles of elongated shape which comprises,

pouring wet concrete into a mold of a shape corresponding to that of the article to be obtained and into a chamber communicating therewith and located above said mold, fluldifying said con crete by rapid vibration exerted on said chamtained in the mold is subjected to a pressure sufficiently low for permitting relative displacements of the elements of the concrete under the eifectof the vibrations, stopping the vibration when the concrete has become firm in said mold and finally reducing the volume of the concrete. by deforming the'moldin such manneras to reduce the area of "the section thereof at right angles to its length, whereby the concrete in the mold is sub 1 jected to a high pressure.

4. A method of manufacturing articles of concrete which consists in pouring wet concrete into a mold, fluidlfying said concrete by rapidly vibrating it and simultaneously subjecting said conbet and said mold, whereby the liquid. mass con- 

